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Title: Measurement of the transmission phase of an electron in a quantum two-path interferometer

A quantum two-path interferometer allows for direct measurement of the transmission phase shift of an electron, providing useful information on coherent scattering problems. In mesoscopic systems, however, the two-path interference is easily smeared by contributions from other paths, and this makes it difficult to observe the true transmission phase shift. To eliminate this problem, multi-terminal Aharonov-Bohm (AB) interferometers have been used to derive the phase shift by assuming that the relative phase shift of the electrons between the two paths is simply obtained when a smooth shift of the AB oscillations is observed. Nevertheless, the phase shifts using such a criterion have sometimes been inconsistent with theory. On the other hand, we have used an AB ring contacted to tunnel-coupled wires and acquired the phase shift consistent with theory when the two output currents through the coupled wires oscillate with well-defined anti-phase. Here, we investigate thoroughly these two criteria used to ensure a reliable phase measurement, the anti-phase relation of the two output currents, and the smooth phase shift in the AB oscillation. We confirm that the well-defined anti-phase relation ensures a correct phase measurement with a quantum two-path interference. In contrast, we find that even in a situation wheremore » the anti-phase relation is less well-defined, the smooth phase shift in the AB oscillation can still occur but does not give the correct transmission phase due to contributions from multiple paths. This indicates that the phase relation of the two output currents in our interferometer gives a good criterion for the measurement of the true transmission phase, while the smooth phase shift in the AB oscillation itself does not.« less
Authors:
;  [1] ;  [1] ;  [2] ;  [3] ;  [4] ; ;  [5] ;  [1] ;  [6]
  1. Department of Applied Physics, University of Tokyo, Bunkyo-ku, Tokyo 113-8656 (Japan)
  2. (Japan)
  3. Université Grenoble Alpes, Institut NEEL, F-38042 Grenoble (France)
  4. (France)
  5. Lehrstuhl für Angewandte Festkörperphysik, Ruhr-Universität Bochum, Universitätsstraße 150, 44780 Bochum (Germany)
  6. (CEMS), RIKEN, Wako, Saitama 351-0198 (Japan)
Publication Date:
OSTI Identifier:
22489095
Resource Type:
Journal Article
Resource Relation:
Journal Name: Applied Physics Letters; Journal Volume: 107; Journal Issue: 6; Other Information: (c) 2015 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; AHARONOV-BOHM EFFECT; COHERENT SCATTERING; CURRENTS; INTERFERENCE; INTERFEROMETERS; OSCILLATIONS; PHASE SHIFT; TRANSMISSION; WIRES